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Growth Kinetics of nanocrystals and nanorods by Employing Small-angle X-ray Scattering (SAXS) and Other Techniques

Journal of Materials Science & Technology 2008年第4期24卷 615-627页

作者： Kanishka BISWAS neenu VArGHESE c.n.r.rao chemistry and Physics of Materials Unit DST Nanoscience Unit and CSIR Centre of Excellence in ChemistryJawaharlal Nehru Centre for Advanced Scientific ResearchJakkur P.O.Bangalore 560064India Solid State and Structural Chemistry UnitIndian Institute of ScienceBangalore 560012India chemistry and Physics of Materials Unit DST Nanoscience Unit and CSIR Centre of Excellence in ChemistryJawaharlal Nehru Centre for Advanced Scientific ResearchJakkur P.O.Bangalore 560064India

In this article, we report the results of our detailed investigations of the growth kinetics of zero-dimensional nanocrystals as well as one-dimensional nanorods by the combined use of small angel X-ray scattering （SAXS）, transmission electron microscopy （TEM） along with other physical techniques. The study includes growth kinetics of gold nanocrystals formed by the reduction of HAucl4 by tetrakis（hydroxymethyl） phosphonium chloride in aqueous solution, of cdSe nanocrystals formed by the reaction of cadmium stearate and selenium under solvothermal conditions, and of ZnO nanorods formed by the reaction of zinc acetate with sodium hydroxide under solvothermal conditions in the absence and presence of capping agents. The growth of gold nanocrystals does not follow the diffusion-limited Ostwald ripening, and instead follows a Sigmoidal rate curve. The heat change associated with the growth determined by isothermal titration calorimetry is about 10 kcal·mol^-1 per I nm increase in the diameter of the nanocrystals. In the case of cdSe nanocrystals also, the growth mechanism deviates from diffusion-limited growth and follows a combined model containing both diffusion and surface reaction terms. Our study of the growth kinetics of uncapped and poly（vinyl pyrollidone）（PVP）-capped ZnO nanorods has yielded interesting insights. We observe small nanocrystals next to the ZnO nanorods after a lapse of time in addition to periodic focusing and defocusing of the width of the length distribution. These observations lend support to the diffusion-limited growth model for the growth of uncapped ZnO nanorods. Accordingly, the time dependence on the length of uncapped nanorods follows the L3 law as required for diffusion-limited Ostwald ripening. The PVP-capped nanorods, however, show a time dependence, which is best described by a combination of diffusion （L^3） and surface reaction （L^2） terms.

关键词： Growth kinetics Gold nanocrystals cdSe nanocrystals ZnO nanorods Small angle X-ray scattering Transmission electron microscopy Ostwald ripening and sigmoidal growth

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Structural behaviour of carbon single wall nanotubes under high pressure

Structural behaviour of carbon single wall nanotubes under h...

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18th International conference on High Pressure Science and Technology

作者： Surinder M Sharma S.Karmakar S.K.Sikka Pallavi V.Teredesai A.K.Sood A.Govindaraj c.n.r.rao High Pressure Physics Division Bhabha Atomic Research CenterMumbai 400085India High Pressure Physics Division Bhabha Atomic Research CenterMumbai 400085India High Pressure Physics Division Bhabha Atomic Research CenterMumbai 400085India Department of Physics Indian Institute of ScienceBangalore 560012India Department of Physics Indian Institute of ScienceBangalore 560012India Chemistry and Physics of Materials UnitJawaharlal Nehru Centre for Advanced Scientific ResearchJakkur CampusJakkur P.O.Bangalore 560064India chemistry and Physics of Materials Unit Jawaharlal Nehru Centre for Advanced Scientific ResearchJakkur CampusJakkur P.O.Bangalore 560064India chemistry and Physics of Materials Unit Jawaharlal Nehru Centre for Advanced Scientific ResearchJakkur CampusJakkur P.O.Bangalore 560064India

＜正＞Single walled carbon nanotubes （SWnTs） can be viewed as tubes formed by the conformal mapping of graphite strips onto cylindrical surfaces. When stacked in bundles, these tubes form a two dimensional triangular lattice. In addition to many interesting and useful physical properties1 of SWnTs, these have been predicted to have remarkable mechanical resilience, such as reversible bending of isolated tubes to -110° 2. recently several high pressure raman studies have been carried out to understand the behaviour under high pressure. Based on these studies, existence of a structural phase transformation at 1.7 GPa3 and polygonization of tubes at - 2.5 GPa4 has been suggested. Another raman investigation indicates a reversible phase transformation at 10 GPa5. To investigate the nature of structural changes under pressure, we have carried out in-situ high pressure x-ray diffraction study on SWnTs up to 13 GPa. These experiments were carried out at the SPringS synchrotron facility. Observed variation of the d-spacings as a function of pressure is shown in Fig. 1. Vanishing of the strongest and only recorded diffraction line （100） of the SWnTs show that the carbon nanotube bundles loose the triangular translational order beyond 10 GPa. However, before losing its translational coherence, the two-dimensional lattice softens substantially as is displayed by an upward jump of dioo of SWnTs in Fig. 1. This is rationalizable in terms of the formation of heterogeneous fins like structures, which may help reduce the average basal strain. These results also provide an explanation for the unusual downward jump of tangential mode of the raman results at this pressure.5 On release of pressure, the tubes regain the triangular lattice structure. These experimental observations validate the predicted remarkable mechanical resilience of the carbon nanotubes. Our data, which represents hydrostatic environment, gives the bulk modulus to be 34 GPa, which is more than a

关键词： High pressure Single Wall carbon nanoTubes (SWnTs) X-ray diffraction

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在通讯、能源和交通运输方面需要革新的高技术材料

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世界科学 1990年第3期 33-35页

作者： c.n.r.rao 王凌云史崇生国际纯粹与应用化学协会(IUPAc) 主席教授

引言高技术材料已经对人类生活的质量产生了巨大的影响.—个国家的兴衰程度几乎与利用这些材料的数量直接相关。事实上,我们可以把利用高技术材料的量作为一个指数,据此把发达国家与发展中国家明显地区别开来。过去几年中,发达国家在这... 详细信息

引言高技术材料已经对人类生活的质量产生了巨大的影响.—个国家的兴衰程度几乎与利用这些材料的数量直接相关。事实上,我们可以把利用高技术材料的量作为一个指数,据此把发达国家与发展中国家明显地区别开来。过去几年中,发达国家在这些高技术工业方面的投资是巨大的,某些材料的投资得到了天文数字大小。当今发展最快的、或许也是社会最需要的就是与材料有关的工业。不幸的是,这些高级材料并未进入

关键词：研究与开发研究与发展不发达国家高技术能源新闻通讯

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Diabetic peripheral neuropathy and neuromodulation techniques:a systematic review of progress and prospects

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neural regeneration research 2025年第8期20卷 2218-2230页

作者： rahul Mittal Keelin McKenna Grant Keith Evan McKenna Joana r.n.Lemos Jeenu Mittal Khemraj Hirani Diabetes research Institute University of Miami Miller School of MedicineMiamiFLUSA Department of Otolaryngology University of Miami Miller School of MedicineMiamiFLUSA Herbert Wertheim college of Medicine Florida International UniversityMiamiFLUSA School of Medicine and Public Health University of WisconsinMadisonWIUSA

neuromodulation for diabetic peripheral neuropathy represents a significant area of interest in the management of chronic pain associated with this *** peripheral neuropathy,a common complication of diabetes,is characterized by nerve damage due to high blood sugar levels that lead to symptoms,such as pain,tingling,and numbness,primarily in the hands and *** aim of this systematic review was to evaluate the efficacy of neuromodulatory techniques as potential therapeutic interventions for patients with diabetic peripheral neuropathy,while also examining recent developments in this *** investigation encompassed an array of neuromodulation methods,including frequency rhythmic electrical modulated systems,dorsal root ganglion stimulation,and spinal cord *** systematic review suggests that neuromodulatory techniques may be useful in the treatment of diabetic peripheral *** the advantages of these treatments will enable physicians and other healthcare providers to offer additional options for patients with symptoms refractory to standard pharmacologic *** these efforts,we may improve quality of life and increase functional capacity in patients suffering from complications related to diabetic neuropathy.

关键词： diabetes mellitus diabetic peripheral neuropathy neuromodulation neurostimulation therapy non-pharmacological treatment pain management

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Artificial neural network approach for prediction of stress–strain curve of near b titanium alloy

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rare Metals 2014年第3期33卷 249-257页

作者： Srinivasu Gangi Setti r.n.rao Mechanical Engineering National Institute of Technology

In the present study, artificial neural network（Ann） approach was used to predict the stress-strain curve of near beta titanium alloy as a function of volume fractions of a and b. This approach is to develop the best possible combination or neural network（nn） to predict the stress-strain curve. In order to achieve this, three different nn architectures（feed-forward back-propagation network,cascade-forward back-propagation network, and layer recurrent network）, three different transfer functions（purelin, Log-Sigmoid, and Tan-Sigmoid）, number of hidden layers（1 and 2）, number of neurons in the hidden layer（s）,and different training algorithms were employed. Ann training modules, the load in terms of strain, and volume fraction of a are the inputs and the stress as an *** system was trained using the prepared training set（a,16 % a, 40 % a, and b stress-strain curves）. After training process, test data were used to check system accuracy. It is observed that feed-forward back-propagation network is the fastest, and Log-Sigmoid transfer function is giving the best results. Finally, layer recurrent nn with a single hidden layer consists of 11 neurons, and Log-Sigmoid transfer function using trainlm as training algorithm is giving good result, and average relative error is1.27 ± 1.45 %. In two hidden layers, layer recurrent nn consists of 7 neurons in each hidden layer with trainrp as the training algorithm having the transfer function of LogSigmoid which gives better results. As a result, the nn is founded successful for the prediction of stress-strain curve of near b titanium alloy.

关键词： Artificial neural network (Ann) Stressstrain curve Titanium alloys

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Separation of Metallic and Semiconducting Single-Walled carbon nanotubes Through Fluorous chemistry

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nano research 2009年第3期2卷 183-191页

作者： Sandeep Ghosh n.r.rao chemistry and Physics of Materials Unit DST unit on Nanoscience and CSIR Centre of Excellence in ChemistryJawaharlal Nehru Centre for Advanced Scientifi c ResearchJakkur P.O.Bangalore-560064India Solid State and Structural chemistry Unit Indian Institute of ScienceBangalore-560012India

Separation of metallic from semiconducting single-walled carbon nanotubes has been a major challenge for some time and some previous efforts have resulted in partial success. We have accomplished the separation effectively by employing fl uorous chemistry wherein the diazonium salt of 4-heptadecafl uorooc tylaniline selectively reacts with the metallic nanotubes present in the mixture of nanotubes. The resulting fl uoroderivative was extracted in perfl uorohexane leaving the semiconducting nanotubes in the aqueous layer. The products have been characterized by both raman and electronic absorption spectroscopy. The method avoids the cumbersome centrifugation step required by some other procedures.

关键词： carbon nanotubes metallic semiconducting fl uorous separation

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Quantum counterfactuality with identical particles

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communications in Theoretical Physics 2023年第6期75卷 59-65页

作者： Vinod n rao Anindita Banerjee r Srikanth Theoretical Sciences Division Poornaprajna Institute of Scientific ResearchBidalurBengaluru—562164India Graduate Studies Manipal Academy of Higher EducationManipal—576104India centre of Development of Advanced computing Corporate Research and DevelopmentPune—411008India

Quantum self-interference enables the counterfactual transmission of information,whereby the transmitted bits involve no particles traveling through the *** this work,we show how counterfactuality can be realized even when the self-interference is replaced by interference between identical ***,the facet of indistinguishability called forth here is associated with first-order coherence,and is different from the usual notion of indistinguishability associated with the(anti-)commutation relations of mode *** an experimental perspective,the simplest implementation of the proposed idea can be realized by slight modifications to existing protocols for differential-phase-shift quantum key distribution or interaction-free measurement.

关键词： quantum cryptography counterfactuality indistinguishability

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Passive activity enhances residual control ability in patients with complete spinal cord injury

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neural regeneration research 2025年第8期20卷 2337-2347页

作者： Yanqing Xiao Mingming Gao Zejia He Jia Zheng Hongming Bai Jia-Sheng rao Guiyun Song Wei Song Xiaoguang Li Beijing Key Laboratory for Biomaterials and neural regeneration Beijing Advanced Innovation Center for Biomedical EngineeringSchool of Biological Science and Medical EngineeringBeihang UniversityBeijingChina Department of rehabilitation Evaluation China Rehabilitation Research CenterBeijingChina cardiac center Beijing Children’s HospitalCapital Medical UniversityBeijingChina The State Key Laboratory of Virtual reality Technology and Systems Beihang UniversityBeijingChina Department of rehabilitation Engineering China Rehabilitation Science InstituteBeijingChina

Patients with complete spinal cord injury retain the potential for volitional muscle activity in muscles located below the spinal injury ***,because of prolonged inactivity,initial attempts to activate these muscles may not effectively engage any of the remaining neurons in the descending pathway.A previous study unexpectedly found that a brief clinical round of passive activity significantly increased volitional muscle activation,as measured by surface *** this study,we further explored the effect of passive activity on surface electromyographic signals during volitional control tasks among individuals with complete spinal cord *** patients with chronic complete thoracic spinal cord injury were *** electromyography data from eight major leg muscles were acquired and compared before and after the passive activity *** results indicated that the passive activity led to an increased number of activated volitional muscles and an increased frequency of *** the cumulative root mean square of surface electromyography amplitude for volitional control of movement showed a slight increase after passive activity,the difference was not statistically *** findings suggest that brief passive activity may enhance the ability to initiate volitional muscle activity during surface electromyography tasks and underscore the potential of passive activity for improving residual motor control among patients with motor complete spinal cord injury.

关键词： complete spinal cord injury cycle training epidural electrical stimulation motor training passive activity physiological state spinal cord circuit surface electromyography volitional control task

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3D tomographic analysis of equatorial plasma bubble using GnSS-TEc data from Indonesian GnSS network

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Earth and Planetary Physics 2025年第1期9卷 127-136页

作者： Ihsan naufal Muafiry Prayitno Abadi Teguh n.Pratama Dyah r.Martiningrum Sri Ekawati Yuandhika GWismaya Febrylian Fchabibi Gatot HPramono research center for climate and Atmosphere Indonesian National Research and Innovation Agency(BRIN)BandungIndonesia Indonesian Geospatial Information Agency(BIG) JakartaIndonesia Dept.of Physics Faculty of ScienceUniversiti Teknologi MalaysiaJohor BahruMalaysia Dept.Earth Planet Sci. Hokkaido UniversitySapporoJapan School of Electrical Engineering Telkom UniversityBandungIndonesia

Equatorial Plasma Bubbles(EPBs)are ionospheric irregularities that take place near the magnetic *** most commonly occur after sunset during the equinox months,although they can also be observed during other *** phenomenon significantly disrupts radio wave signals essential to communication and navigation *** national network of Global navigation Satellite System(GnSS)receivers in Indonesia(>30°longitudinal range)provides an opportunity for detailed EPB *** explore this,we conducted preliminary 3D tomography of total electron content(TEc)data captured by GnSS receivers following a geomagnetic storm on December 3,2023,when at least four EPB clusters occurred in the Southeast Asian *** and extracted TEc depletion with a 120-minute running average were then used as inputs for a 3D tomography *** 2D spatial distribution consistently captured the four EPB clusters over *** tomography results were validated through a classical checkerboard test and comparisons with other ionospheric data sources,such as the Global Ionospheric Map(GIM)and International reference Ionosphere(IrI)*** of the results demonstrates the capability of the Indonesian GnSS network to measure peak ionospheric *** findings highlight the potential for future three-dimensional research of plasma bubbles in low-latitude regions using existing GnSS networks,with extensive longitudinal coverage.

关键词： EPB Indonesian GnSS network 3D tomography

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Validation of Transverse Phase Space Tomography at TrIUMF

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原子能科学技术 2022年第9期56卷 1760-1773页

作者： rao Y n BAArTMAn r TrIUMF 4004 Wesbrook MallVancouver British ColumbiaV6T2A3Canada

Knowledge of the phase space density distribution in details is useful to understand subsequent evolution of the charged particle beam in a transport *** makes the beam tomography very useful in the application for beam *** application is not limited by the beam energy,as opposed to the emittance *** paper presented the simulations and measurements we undertook in TrIUMF beam-lines to validate the maximum entropy(MEnT)technique for the tomographic reconstruction of beam density distribution in the 2-dimensional transverse phase *** profiles were taken with a single wire scanner while changing an upstream quadrupole’s ***,the phase space plots were directly measured with emittance scanner.A close comparison was made on the resulting phase space density distribution and the emittance value at the same location of the *** show good agreement.

关键词： beam tomography maximum entropy algorithm phase space emittance

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